The present disclosure generally relates to intravenous (IV) administration of medical fluids and, in particular, tubing clamps for use with the tubing of IV sets.
Medical procedures often require the IV administration of various fluids such as medications via a programmable pump, gravity-fed IV bag, or injection. For example, liquid saline solution is commonly administered intravenously to patients who cannot take fluids orally and have developed severe dehydration. Typically, the IV fluid administration takes place at periodic intervals over a length of time and patient treatment requires additional delivery of other therapeutic fluids. A catheter is often inserted into the patient's vein, the proximal end of which is connected to medical tubing. The medical tubing in turn is connected to a source of medical fluid, such as an IV bag. In order to avoid repeated direct injections into the patient, sections of the medical tubing between the catheter and the primary fluid source often include “Y” branches, which include connectors. These connectors allow the attachment of syringe devices or other sources of medical fluid to deliver additional medical fluids to the patient via the already implanted catheter. The combination of medical tubing, fitting, and connectors is commonly referred to as an “IV set.”
A positive bolus effect describes the condition in which fluid is flushed out of the connector during removal of the syringe from the connector. A zero bolus effect describes the condition during which no fluid displacement takes place, and fluid is neither drawn into nor flushed out of the connector during removal of the syringe.
A problem associated with typical IV sets is the creation of a negative bolus effect upon withdrawal of a syringe from a “Y” connector. A negative bolus effect is generated when a partial vacuum is produced within the connector upon removal of the syringe. This partial vacuum may draw fluid up from the medical line tubing and into the connector. The tubing draws fluid from the catheter connected to the patient, which in turn draws fluid, such as blood, from the patient. This drawing of fluid from the patient into the IV set may contaminate the IV set or blood that is drawn into the IV set may clot and form an obstruction to future fluid flow through the IV set.
One method of reducing the negative bolus effect is to provide a clamp over the tubing to be used in conjunction with mating or removing a syringe or other source of medical fluid. The clamp is attached to a portion of the medical line tubing that is downstream from the connector and pinches the tubing closed. The negative bolus effect is therefore limited to the section of tubing between the Y-connector and the clamp. There may be a partial vacuum created in the line, however, and this partial vacuum will also cause a retrograde flow of blood or other fluid from the patient if the clamp is released.
The negative bolus effect may be also be overcome by use of a positive bolus connector. Such a connector, typically a female needleless connector, has a variable volume internal flow path that expands when a male connector is mated to it. When the male connector is removed, the internal flow path contracts and expels fluid into the line, thereby creating a positive bolus. A user accustomed to standard connectors may actuate a standard tubing clamp just downstream of the connector, as described above, before disconnecting the positive bolus connector, thereby defeating the positive bolus feature of the connector.
There is a need for a simple-to-use positive bolus clamp that can be used with all types of connectors effectively create a positive bolus of fluid.
The above and other needs are met by the disclosed embodiments, which provide a clamp apparatus for advantageously preventing fluid flow through resilient flexible tubing at an upstream location and collapsing a down-stream portion of the tubing to provide a positive bolus of fluid out of the tubing towards the patient.
In certain embodiments, a clamp for clamping flexible tubing is disclosed. The clamp includes a body having a first portion, a second portion, a first passage through the first portion, and a second passage through the second portion. The first passage is configured to compress a first length of the flexible tubing when the flexible tubing is displaced laterally into the first passage. The second passage is configured to compress a second length of the flexible tubing that does not overlap the first length when the flexible tubing is displaced laterally into the second passage.
In certain embodiments, a clamp for clamping flexible tubing is disclosed that includes a first element having a first surface with a first corner, a second element having a second surface with a second corner; and a flexible element coupled to the first and second elements. The flexible element is configured such that when the clamp is not actuated, the first and second surfaces are disposed at an angle to each other. The flexible element is further configured such that when the first element is displaced toward the second element with the flexible tubing between the first and second elements, the first and second corners cooperate to sealingly compress a first length of the flexible tubing. As the first element is further displaced toward the second element, the first element rotates with respect to the second element such that the first and second surfaces cooperate to sealingly compress a second length of the flexible tubing.
In certain embodiments, a method of clamping flexible tubing is disclosed. The method includes the steps of laterally displacing the flexible tubing into a first passage configured to sealingly compress a first length of the flexible tubing and further displacing laterally the flexible tubing into a second passage configured to sealingly compress a second length of the flexible tubing that does not overlap the first length.
In certain embodiments, a method of clamping flexible tubing is disclosed. The method includes the steps of displacing a first element having a first surface with a first corner toward a second element having a second surface with a second corner with the flexible tubing disposed between the first and second surfaces until the first and second corners cooperate to sealingly compress the flexible tubing and further displacing the first element toward the second element thereby causing the first element to rotate relative to the second element such that the first and second surfaces cooperate to sealingly compress a second length of the flexible tubing.